Iceland raises alert at active volcano

REYKJAVIK - Iceland has warned of the risk of an eruption at one of its largest volcanoes, four years after millions of air travelers were grounded by a huge ash cloud from another volcano.

The country's meteorological office raised the alert at the Bardabunga volcano to "orange," its second most serious, signaling increased activity and a heightened risk of eruption. It follows intense seismic activity recorded at Bardabunga, which lies in the southeast of the country, since Saturday.

An eruption of Iceland's Eyjafjoell volcano in April 2010 stranded more than eight million travelers as a vast cloud of volcanic ash spread across Europe.